1 /* 2 * linux/include/linux/nfs_fs.h 3 * 4 * Copyright (C) 1992 Rick Sladkey 5 * 6 * OS-specific nfs filesystem definitions and declarations 7 */ 8 9 #ifndef _LINUX_NFS_FS_H 10 #define _LINUX_NFS_FS_H 11 12 #include <linux/magic.h> 13 14 /* Default timeout values */ 15 #define NFS_DEF_UDP_TIMEO (11) 16 #define NFS_DEF_UDP_RETRANS (3) 17 #define NFS_DEF_TCP_TIMEO (600) 18 #define NFS_DEF_TCP_RETRANS (2) 19 20 #define NFS_MAX_UDP_TIMEOUT (60*HZ) 21 #define NFS_MAX_TCP_TIMEOUT (600*HZ) 22 23 #define NFS_DEF_ACREGMIN (3) 24 #define NFS_DEF_ACREGMAX (60) 25 #define NFS_DEF_ACDIRMIN (30) 26 #define NFS_DEF_ACDIRMAX (60) 27 28 /* 29 * When flushing a cluster of dirty pages, there can be different 30 * strategies: 31 */ 32 #define FLUSH_SYNC 1 /* file being synced, or contention */ 33 #define FLUSH_STABLE 4 /* commit to stable storage */ 34 #define FLUSH_LOWPRI 8 /* low priority background flush */ 35 #define FLUSH_HIGHPRI 16 /* high priority memory reclaim flush */ 36 #define FLUSH_COND_STABLE 32 /* conditional stable write - only stable 37 * if everything fits in one RPC */ 38 39 #ifdef __KERNEL__ 40 41 #include <linux/in.h> 42 #include <linux/mm.h> 43 #include <linux/pagemap.h> 44 #include <linux/rbtree.h> 45 #include <linux/rwsem.h> 46 #include <linux/wait.h> 47 48 #include <linux/sunrpc/debug.h> 49 #include <linux/sunrpc/auth.h> 50 #include <linux/sunrpc/clnt.h> 51 52 #include <linux/nfs.h> 53 #include <linux/nfs2.h> 54 #include <linux/nfs3.h> 55 #include <linux/nfs4.h> 56 #include <linux/nfs_xdr.h> 57 #include <linux/nfs_fs_sb.h> 58 59 #include <linux/mempool.h> 60 61 /* 62 * These are the default flags for swap requests 63 */ 64 #define NFS_RPC_SWAPFLAGS (RPC_TASK_SWAPPER|RPC_TASK_ROOTCREDS) 65 66 /* 67 * NFSv3/v4 Access mode cache entry 68 */ 69 struct nfs_access_entry { 70 struct rb_node rb_node; 71 struct list_head lru; 72 unsigned long jiffies; 73 struct rpc_cred * cred; 74 int mask; 75 }; 76 77 struct nfs_lock_context { 78 atomic_t count; 79 struct list_head list; 80 struct nfs_open_context *open_context; 81 fl_owner_t lockowner; 82 pid_t pid; 83 }; 84 85 struct nfs4_state; 86 struct nfs_open_context { 87 struct nfs_lock_context lock_context; 88 struct dentry *dentry; 89 struct rpc_cred *cred; 90 struct nfs4_state *state; 91 fmode_t mode; 92 93 unsigned long flags; 94 #define NFS_CONTEXT_ERROR_WRITE (0) 95 int error; 96 97 struct list_head list; 98 }; 99 100 struct nfs_open_dir_context { 101 struct rpc_cred *cred; 102 unsigned long attr_gencount; 103 __u64 dir_cookie; 104 __u64 dup_cookie; 105 signed char duped; 106 }; 107 108 /* 109 * NFSv4 delegation 110 */ 111 struct nfs_delegation; 112 113 struct posix_acl; 114 115 /* 116 * nfs fs inode data in memory 117 */ 118 struct nfs_inode { 119 /* 120 * The 64bit 'inode number' 121 */ 122 __u64 fileid; 123 124 /* 125 * NFS file handle 126 */ 127 struct nfs_fh fh; 128 129 /* 130 * Various flags 131 */ 132 unsigned long flags; /* atomic bit ops */ 133 unsigned long cache_validity; /* bit mask */ 134 135 /* 136 * read_cache_jiffies is when we started read-caching this inode. 137 * attrtimeo is for how long the cached information is assumed 138 * to be valid. A successful attribute revalidation doubles 139 * attrtimeo (up to acregmax/acdirmax), a failure resets it to 140 * acregmin/acdirmin. 141 * 142 * We need to revalidate the cached attrs for this inode if 143 * 144 * jiffies - read_cache_jiffies >= attrtimeo 145 * 146 * Please note the comparison is greater than or equal 147 * so that zero timeout values can be specified. 148 */ 149 unsigned long read_cache_jiffies; 150 unsigned long attrtimeo; 151 unsigned long attrtimeo_timestamp; 152 153 unsigned long attr_gencount; 154 /* "Generation counter" for the attribute cache. This is 155 * bumped whenever we update the metadata on the 156 * server. 157 */ 158 unsigned long cache_change_attribute; 159 160 struct rb_root access_cache; 161 struct list_head access_cache_entry_lru; 162 struct list_head access_cache_inode_lru; 163 #ifdef CONFIG_NFS_V3_ACL 164 struct posix_acl *acl_access; 165 struct posix_acl *acl_default; 166 #endif 167 168 /* 169 * This is the cookie verifier used for NFSv3 readdir 170 * operations 171 */ 172 __be32 cookieverf[2]; 173 174 /* 175 * This is the list of dirty unwritten pages. 176 */ 177 struct radix_tree_root nfs_page_tree; 178 179 unsigned long npages; 180 unsigned long ncommit; 181 182 /* Open contexts for shared mmap writes */ 183 struct list_head open_files; 184 185 /* Number of in-flight sillydelete RPC calls */ 186 atomic_t silly_count; 187 /* List of deferred sillydelete requests */ 188 struct hlist_head silly_list; 189 wait_queue_head_t waitqueue; 190 191 #ifdef CONFIG_NFS_V4 192 struct nfs4_cached_acl *nfs4_acl; 193 /* NFSv4 state */ 194 struct list_head open_states; 195 struct nfs_delegation __rcu *delegation; 196 fmode_t delegation_state; 197 struct rw_semaphore rwsem; 198 199 /* pNFS layout information */ 200 struct pnfs_layout_hdr *layout; 201 atomic_t commits_outstanding; 202 #endif /* CONFIG_NFS_V4*/ 203 #ifdef CONFIG_NFS_FSCACHE 204 struct fscache_cookie *fscache; 205 #endif 206 struct inode vfs_inode; 207 }; 208 209 /* 210 * Cache validity bit flags 211 */ 212 #define NFS_INO_INVALID_ATTR 0x0001 /* cached attrs are invalid */ 213 #define NFS_INO_INVALID_DATA 0x0002 /* cached data is invalid */ 214 #define NFS_INO_INVALID_ATIME 0x0004 /* cached atime is invalid */ 215 #define NFS_INO_INVALID_ACCESS 0x0008 /* cached access cred invalid */ 216 #define NFS_INO_INVALID_ACL 0x0010 /* cached acls are invalid */ 217 #define NFS_INO_REVAL_PAGECACHE 0x0020 /* must revalidate pagecache */ 218 #define NFS_INO_REVAL_FORCED 0x0040 /* force revalidation ignoring a delegation */ 219 220 /* 221 * Bit offsets in flags field 222 */ 223 #define NFS_INO_ADVISE_RDPLUS (0) /* advise readdirplus */ 224 #define NFS_INO_STALE (1) /* possible stale inode */ 225 #define NFS_INO_ACL_LRU_SET (2) /* Inode is on the LRU list */ 226 #define NFS_INO_FLUSHING (4) /* inode is flushing out data */ 227 #define NFS_INO_FSCACHE (5) /* inode can be cached by FS-Cache */ 228 #define NFS_INO_FSCACHE_LOCK (6) /* FS-Cache cookie management lock */ 229 #define NFS_INO_COMMIT (7) /* inode is committing unstable writes */ 230 #define NFS_INO_PNFS_COMMIT (8) /* use pnfs code for commit */ 231 #define NFS_INO_LAYOUTCOMMIT (9) /* layoutcommit required */ 232 #define NFS_INO_LAYOUTCOMMITTING (10) /* layoutcommit inflight */ 233 234 static inline struct nfs_inode *NFS_I(const struct inode *inode) 235 { 236 return container_of(inode, struct nfs_inode, vfs_inode); 237 } 238 239 static inline struct nfs_server *NFS_SB(const struct super_block *s) 240 { 241 return (struct nfs_server *)(s->s_fs_info); 242 } 243 244 static inline struct nfs_fh *NFS_FH(const struct inode *inode) 245 { 246 return &NFS_I(inode)->fh; 247 } 248 249 static inline struct nfs_server *NFS_SERVER(const struct inode *inode) 250 { 251 return NFS_SB(inode->i_sb); 252 } 253 254 static inline struct rpc_clnt *NFS_CLIENT(const struct inode *inode) 255 { 256 return NFS_SERVER(inode)->client; 257 } 258 259 static inline const struct nfs_rpc_ops *NFS_PROTO(const struct inode *inode) 260 { 261 return NFS_SERVER(inode)->nfs_client->rpc_ops; 262 } 263 264 static inline __be32 *NFS_COOKIEVERF(const struct inode *inode) 265 { 266 return NFS_I(inode)->cookieverf; 267 } 268 269 static inline unsigned NFS_MINATTRTIMEO(const struct inode *inode) 270 { 271 struct nfs_server *nfss = NFS_SERVER(inode); 272 return S_ISDIR(inode->i_mode) ? nfss->acdirmin : nfss->acregmin; 273 } 274 275 static inline unsigned NFS_MAXATTRTIMEO(const struct inode *inode) 276 { 277 struct nfs_server *nfss = NFS_SERVER(inode); 278 return S_ISDIR(inode->i_mode) ? nfss->acdirmax : nfss->acregmax; 279 } 280 281 static inline int NFS_STALE(const struct inode *inode) 282 { 283 return test_bit(NFS_INO_STALE, &NFS_I(inode)->flags); 284 } 285 286 static inline int NFS_FSCACHE(const struct inode *inode) 287 { 288 return test_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags); 289 } 290 291 static inline __u64 NFS_FILEID(const struct inode *inode) 292 { 293 return NFS_I(inode)->fileid; 294 } 295 296 static inline void set_nfs_fileid(struct inode *inode, __u64 fileid) 297 { 298 NFS_I(inode)->fileid = fileid; 299 } 300 301 static inline void nfs_mark_for_revalidate(struct inode *inode) 302 { 303 struct nfs_inode *nfsi = NFS_I(inode); 304 305 spin_lock(&inode->i_lock); 306 nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS; 307 if (S_ISDIR(inode->i_mode)) 308 nfsi->cache_validity |= NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA; 309 spin_unlock(&inode->i_lock); 310 } 311 312 static inline int nfs_server_capable(struct inode *inode, int cap) 313 { 314 return NFS_SERVER(inode)->caps & cap; 315 } 316 317 static inline int NFS_USE_READDIRPLUS(struct inode *inode) 318 { 319 return test_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags); 320 } 321 322 static inline void nfs_set_verifier(struct dentry * dentry, unsigned long verf) 323 { 324 dentry->d_time = verf; 325 } 326 327 /** 328 * nfs_save_change_attribute - Returns the inode attribute change cookie 329 * @dir - pointer to parent directory inode 330 * The "change attribute" is updated every time we finish an operation 331 * that will result in a metadata change on the server. 332 */ 333 static inline unsigned long nfs_save_change_attribute(struct inode *dir) 334 { 335 return NFS_I(dir)->cache_change_attribute; 336 } 337 338 /** 339 * nfs_verify_change_attribute - Detects NFS remote directory changes 340 * @dir - pointer to parent directory inode 341 * @chattr - previously saved change attribute 342 * Return "false" if the verifiers doesn't match the change attribute. 343 * This would usually indicate that the directory contents have changed on 344 * the server, and that any dentries need revalidating. 345 */ 346 static inline int nfs_verify_change_attribute(struct inode *dir, unsigned long chattr) 347 { 348 return chattr == NFS_I(dir)->cache_change_attribute; 349 } 350 351 /* 352 * linux/fs/nfs/inode.c 353 */ 354 extern int nfs_sync_mapping(struct address_space *mapping); 355 extern void nfs_zap_mapping(struct inode *inode, struct address_space *mapping); 356 extern void nfs_zap_caches(struct inode *); 357 extern void nfs_invalidate_atime(struct inode *); 358 extern struct inode *nfs_fhget(struct super_block *, struct nfs_fh *, 359 struct nfs_fattr *); 360 extern int nfs_refresh_inode(struct inode *, struct nfs_fattr *); 361 extern int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr); 362 extern int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fattr); 363 extern int nfs_getattr(struct vfsmount *, struct dentry *, struct kstat *); 364 extern int nfs_permission(struct inode *, int); 365 extern int nfs_open(struct inode *, struct file *); 366 extern int nfs_release(struct inode *, struct file *); 367 extern int nfs_attribute_timeout(struct inode *inode); 368 extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode); 369 extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *); 370 extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping); 371 extern int nfs_setattr(struct dentry *, struct iattr *); 372 extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr); 373 extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx); 374 extern void put_nfs_open_context(struct nfs_open_context *ctx); 375 extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_cred *cred, fmode_t mode); 376 extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, struct rpc_cred *cred, fmode_t f_mode); 377 extern void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx); 378 extern struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx); 379 extern void nfs_put_lock_context(struct nfs_lock_context *l_ctx); 380 extern u64 nfs_compat_user_ino64(u64 fileid); 381 extern void nfs_fattr_init(struct nfs_fattr *fattr); 382 extern unsigned long nfs_inc_attr_generation_counter(void); 383 384 extern struct nfs_fattr *nfs_alloc_fattr(void); 385 386 static inline void nfs_free_fattr(const struct nfs_fattr *fattr) 387 { 388 kfree(fattr); 389 } 390 391 extern struct nfs_fh *nfs_alloc_fhandle(void); 392 393 static inline void nfs_free_fhandle(const struct nfs_fh *fh) 394 { 395 kfree(fh); 396 } 397 398 /* 399 * linux/fs/nfs/nfsroot.c 400 */ 401 extern int nfs_root_data(char **root_device, char **root_data); /*__init*/ 402 /* linux/net/ipv4/ipconfig.c: trims ip addr off front of name, too. */ 403 extern __be32 root_nfs_parse_addr(char *name); /*__init*/ 404 405 /* 406 * linux/fs/nfs/file.c 407 */ 408 extern const struct inode_operations nfs_file_inode_operations; 409 #ifdef CONFIG_NFS_V3 410 extern const struct inode_operations nfs3_file_inode_operations; 411 #endif /* CONFIG_NFS_V3 */ 412 extern const struct file_operations nfs_file_operations; 413 #ifdef CONFIG_NFS_V4 414 extern const struct file_operations nfs4_file_operations; 415 #endif /* CONFIG_NFS_V4 */ 416 extern const struct address_space_operations nfs_file_aops; 417 extern const struct address_space_operations nfs_dir_aops; 418 419 static inline struct nfs_open_context *nfs_file_open_context(struct file *filp) 420 { 421 return filp->private_data; 422 } 423 424 static inline struct rpc_cred *nfs_file_cred(struct file *file) 425 { 426 if (file != NULL) { 427 struct nfs_open_context *ctx = 428 nfs_file_open_context(file); 429 if (ctx) 430 return ctx->cred; 431 } 432 return NULL; 433 } 434 435 /* 436 * linux/fs/nfs/xattr.c 437 */ 438 #ifdef CONFIG_NFS_V3_ACL 439 extern ssize_t nfs3_listxattr(struct dentry *, char *, size_t); 440 extern ssize_t nfs3_getxattr(struct dentry *, const char *, void *, size_t); 441 extern int nfs3_setxattr(struct dentry *, const char *, 442 const void *, size_t, int); 443 extern int nfs3_removexattr (struct dentry *, const char *name); 444 #else 445 # define nfs3_listxattr NULL 446 # define nfs3_getxattr NULL 447 # define nfs3_setxattr NULL 448 # define nfs3_removexattr NULL 449 #endif 450 451 /* 452 * linux/fs/nfs/direct.c 453 */ 454 extern ssize_t nfs_direct_IO(int, struct kiocb *, const struct iovec *, loff_t, 455 unsigned long); 456 extern ssize_t nfs_file_direct_read(struct kiocb *iocb, 457 const struct iovec *iov, unsigned long nr_segs, 458 loff_t pos); 459 extern ssize_t nfs_file_direct_write(struct kiocb *iocb, 460 const struct iovec *iov, unsigned long nr_segs, 461 loff_t pos); 462 463 /* 464 * linux/fs/nfs/dir.c 465 */ 466 extern const struct inode_operations nfs_dir_inode_operations; 467 #ifdef CONFIG_NFS_V3 468 extern const struct inode_operations nfs3_dir_inode_operations; 469 #endif /* CONFIG_NFS_V3 */ 470 extern const struct file_operations nfs_dir_operations; 471 extern const struct dentry_operations nfs_dentry_operations; 472 473 extern void nfs_force_lookup_revalidate(struct inode *dir); 474 extern int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fh, struct nfs_fattr *fattr); 475 extern int nfs_may_open(struct inode *inode, struct rpc_cred *cred, int openflags); 476 extern void nfs_access_zap_cache(struct inode *inode); 477 478 /* 479 * linux/fs/nfs/symlink.c 480 */ 481 extern const struct inode_operations nfs_symlink_inode_operations; 482 483 /* 484 * linux/fs/nfs/sysctl.c 485 */ 486 #ifdef CONFIG_SYSCTL 487 extern int nfs_register_sysctl(void); 488 extern void nfs_unregister_sysctl(void); 489 #else 490 #define nfs_register_sysctl() 0 491 #define nfs_unregister_sysctl() do { } while(0) 492 #endif 493 494 /* 495 * linux/fs/nfs/namespace.c 496 */ 497 extern const struct inode_operations nfs_mountpoint_inode_operations; 498 extern const struct inode_operations nfs_referral_inode_operations; 499 extern int nfs_mountpoint_expiry_timeout; 500 extern void nfs_release_automount_timer(void); 501 502 /* 503 * linux/fs/nfs/unlink.c 504 */ 505 extern void nfs_complete_unlink(struct dentry *dentry, struct inode *); 506 extern void nfs_block_sillyrename(struct dentry *dentry); 507 extern void nfs_unblock_sillyrename(struct dentry *dentry); 508 extern int nfs_sillyrename(struct inode *dir, struct dentry *dentry); 509 510 /* 511 * linux/fs/nfs/write.c 512 */ 513 extern int nfs_congestion_kb; 514 extern int nfs_writepage(struct page *page, struct writeback_control *wbc); 515 extern int nfs_writepages(struct address_space *, struct writeback_control *); 516 extern int nfs_flush_incompatible(struct file *file, struct page *page); 517 extern int nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int); 518 extern void nfs_writeback_done(struct rpc_task *, struct nfs_write_data *); 519 520 /* 521 * Try to write back everything synchronously (but check the 522 * return value!) 523 */ 524 extern int nfs_wb_all(struct inode *inode); 525 extern int nfs_wb_page(struct inode *inode, struct page* page); 526 extern int nfs_wb_page_cancel(struct inode *inode, struct page* page); 527 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) 528 extern int nfs_commit_inode(struct inode *, int); 529 extern struct nfs_write_data *nfs_commitdata_alloc(void); 530 extern void nfs_commit_free(struct nfs_write_data *wdata); 531 #else 532 static inline int 533 nfs_commit_inode(struct inode *inode, int how) 534 { 535 return 0; 536 } 537 #endif 538 539 static inline int 540 nfs_have_writebacks(struct inode *inode) 541 { 542 return NFS_I(inode)->npages != 0; 543 } 544 545 /* 546 * Allocate nfs_write_data structures 547 */ 548 extern struct nfs_write_data *nfs_writedata_alloc(unsigned int npages); 549 extern void nfs_writedata_free(struct nfs_write_data *); 550 551 /* 552 * linux/fs/nfs/read.c 553 */ 554 extern int nfs_readpage(struct file *, struct page *); 555 extern int nfs_readpages(struct file *, struct address_space *, 556 struct list_head *, unsigned); 557 extern int nfs_readpage_result(struct rpc_task *, struct nfs_read_data *); 558 extern int nfs_readpage_async(struct nfs_open_context *, struct inode *, 559 struct page *); 560 561 /* 562 * Allocate nfs_read_data structures 563 */ 564 extern struct nfs_read_data *nfs_readdata_alloc(unsigned int npages); 565 extern void nfs_readdata_free(struct nfs_read_data *); 566 567 /* 568 * linux/fs/nfs3proc.c 569 */ 570 #ifdef CONFIG_NFS_V3_ACL 571 extern struct posix_acl *nfs3_proc_getacl(struct inode *inode, int type); 572 extern int nfs3_proc_setacl(struct inode *inode, int type, 573 struct posix_acl *acl); 574 extern int nfs3_proc_set_default_acl(struct inode *dir, struct inode *inode, 575 umode_t mode); 576 extern void nfs3_forget_cached_acls(struct inode *inode); 577 #else 578 static inline int nfs3_proc_set_default_acl(struct inode *dir, 579 struct inode *inode, 580 umode_t mode) 581 { 582 return 0; 583 } 584 585 static inline void nfs3_forget_cached_acls(struct inode *inode) 586 { 587 } 588 #endif /* CONFIG_NFS_V3_ACL */ 589 590 /* 591 * inline functions 592 */ 593 594 static inline loff_t nfs_size_to_loff_t(__u64 size) 595 { 596 if (size > (__u64) OFFSET_MAX - 1) 597 return OFFSET_MAX - 1; 598 return (loff_t) size; 599 } 600 601 static inline ino_t 602 nfs_fileid_to_ino_t(u64 fileid) 603 { 604 ino_t ino = (ino_t) fileid; 605 if (sizeof(ino_t) < sizeof(u64)) 606 ino ^= fileid >> (sizeof(u64)-sizeof(ino_t)) * 8; 607 return ino; 608 } 609 610 #define NFS_JUKEBOX_RETRY_TIME (5 * HZ) 611 612 #endif /* __KERNEL__ */ 613 614 /* 615 * NFS debug flags 616 */ 617 #define NFSDBG_VFS 0x0001 618 #define NFSDBG_DIRCACHE 0x0002 619 #define NFSDBG_LOOKUPCACHE 0x0004 620 #define NFSDBG_PAGECACHE 0x0008 621 #define NFSDBG_PROC 0x0010 622 #define NFSDBG_XDR 0x0020 623 #define NFSDBG_FILE 0x0040 624 #define NFSDBG_ROOT 0x0080 625 #define NFSDBG_CALLBACK 0x0100 626 #define NFSDBG_CLIENT 0x0200 627 #define NFSDBG_MOUNT 0x0400 628 #define NFSDBG_FSCACHE 0x0800 629 #define NFSDBG_PNFS 0x1000 630 #define NFSDBG_PNFS_LD 0x2000 631 #define NFSDBG_ALL 0xFFFF 632 633 #ifdef __KERNEL__ 634 635 /* 636 * Enable debugging support for nfs client. 637 * Requires RPC_DEBUG. 638 */ 639 #ifdef RPC_DEBUG 640 # define NFS_DEBUG 641 #endif 642 643 # undef ifdebug 644 # ifdef NFS_DEBUG 645 # define ifdebug(fac) if (unlikely(nfs_debug & NFSDBG_##fac)) 646 # else 647 # define ifdebug(fac) if (0) 648 # endif 649 #endif /* __KERNEL */ 650 651 #endif 652